[FFmpeg-trac] #11056(avformat:closed): Position of key frame incorrect

[FFmpeg]

#11056: Position of key frame incorrect
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             Reporter:  David        |                    Owner:  (none)
  Johansen                           |
                 Type:  defect       |                   Status:  closed
             Priority:  normal       |                Component:  avformat
              Version:  6.1.1        |               Resolution:  invalid
             Keywords:  ffprobe pos  |               Blocked By:
  mp4                                |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by David Johansen):

 Here's an example video that I used to demonstrate what I'm doing and that
 the expected values don't match up:
 https://drive.google.com/file/d/1WxOrSi-
 GNB45nLUUiR4PT7c4H2VurtKk/view?usp=sharing

 Run this command to make a fragmented mp4 with each fragment having a
 single key frame in it:
 `ffmpeg -I input.mp4 -c:v libx264 -copyts -muxdelay 0 -force_key_frames
 source -hls_time 0.9 -hls_init_time 0.9 -hls_list_size 0 -hls_flags
 independent_segments -hls_segment_type fmp4 -f hls index.m3u8`

 Then combine the files into a single file by starting with the init:
 `cat init.mp4 >> output.mp4`
 And then adding the rest of the files:
 `for f in index*.m4s; do echo $f; cat $f >> output.mp4; done`

 I would expect that the size and position of the keyframes would match up
 with the file sizes, but that's not the case:
 `ffprobe -show_entries packet=pos,flags -of csv=p=0 -i output.mp4 | grep
 K`

 Is there something I'm doing incorrectly or an assumption I'm making
 that's not correct?
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/11056#comment:15>
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